This proposal is directed toward analyzing the function(s) of cAMP in macromolecular processes in reproductive tissues. The principal objective is determining the mechanism of action of this and other cyclic nucleotides in modifying protein synthesis in these tissues. Our observation of cyclic nucleotide binding to germinal ribonucleoprotein-like particles is being extended and evaluated in other tissues. Similarly, we intend to continue studies on direct photoaffinity labeling of receptor proteins with cyclic nucleotides, as affected by ultraviolet irradiation. BIBLIOGRAPHIC REFERENCES: Antonoff, R.S., Ferguson, J.J., Jr. & Idelkope, G. Direct Photo-affinity Labeling of Cyclic Nucleotide Binding Proteins with Cyclic AMP. Photochemistry and Photobiology Vol. 23 (1976). Antonoff, R.S., & Ferguson, J.J., Jr. Photoincorporation of H3 Norepinephrine into a Particulate Preparation from Small Intestine. Fed. Proc. (1976).